Mechanical hammer



0d. 6, 1936. l RASCH 2,056,293

` MECHANICAL HAMMER Filed May 18, 1954 3 Sheets-Sheet 1 INVENTQR LUDVIKRASCH ATTORNEY oct.s`,1936.,v L. RASCH 'i f2,o5s,z93

MECHANICAL HAMMER Filed May 18, 1954 3 sheets-sheet '2 INVENTOR LUDVIKRASCH ATTORNEY omn '6, 1936.

L. RAscH MECHANICAL HAMMER' Fil'ed May 18, 1934' INVENTQR LuDvlK RAscHPatented Oct. 6, 1936 UNITED STATES PATENT OFFICE 29 Claims.

The present invention relates to arranging as a member of the hammeraggregate proper a compressor driven by the motor of thetool in such a1'0 manner that the compressor constitutes a part of the completetooland is connected in suitable manner with the carrying sleeve of thedrill', so that the compressor supplies to a sufcient degree blastingair for blowing out dust from the bore. l In such a manner it willalways be possible to obtain the necessary quantity of blasting air,because the compressor capacity may be dimensioned in accordance withDthe occurring requirements. Preferably the compressor may be made as apiston pump, whose piston is in operative connection with the motorpiston proper or with another movable part of the motor.

The simplest embodiment is to connect both pistons together by aconnecting rod. As large quantities of blasting air are required and asthe air surrounding the tool contain frequently stone dust, it is`necessary to purify this air. According to the invention the air inletis therefore provided with a device for centrifuging the inlet air, inorder to remove its dust contents safely. The centrifugation may beobtained by providing the usual cooling air fan of the hammer withblades, so that the air must pass by these blades when passing to thecompressor and to the cooling com- I partment of the motor.

The compressor piston may also be made integral with the motor pistonand operates in an annular pumping chamber in axial alignment of themotor cylinder. In mechanical hammers of this kind it is formerly knownto arrange a separate compartment for air under pressure to supply suchair to the space below the striking piston to return same after itsoperating stroke which is eiected by the explosion pressure of themotor.

The pressure side of the compressor may now advantageously be put incommunication with the said compartment to produce the necessarypressure in this compartment and to maintain same during the operationof the hammer. For this purpose the compartment is provided with a valveycontrolling the connection with the carrying sleeve of the drill andbeing so arranged that the pressure in the compressor chamberwhen/passing beyond -a definite limit forces the valve into a position,wherein the connection with the sleeve (Cl. 12S- 7) is open so that theair under pressure is supplied to the bore, as soon las the said limithas been surpassed. The valve may simultaneously l be made as a safetyvalve opening to the atmosphere, when the pressure in the compartmentin- 5;

creases beyond the said limit.

An embodiment of the invention is illustrated in the accompanying'drawings.

Figure 1 is a vertical sectional view taken axially through a mechanicalhammer illustrat- 10 ing a preferred embodiment of the invention andtaken approximately on the line I-l of Figure 3.

Figure 2 is a similar view through the hammer, takenl on the brokenplane indicated by the line 2-2 of Figure 3 and showing a modied form of15 the compressor element;

Figure 3 is an enlarged horizontal cross sectional view taken on the'plane indicated by the line 3-3 of\Figure 1; and

' Figure 4 is a view similarto that of Figure 2v showing still anothermodification.

The hammer is provided at its lower end with a carrying sleeve or drillmounting I for the drill 2. 'Ihe sleeve is journalled in a lower cap 3in the hammer casing 4 which encloses a cylinder 5 for a motor withinternal combustion. The space within the interior of the casing 4 andexterior of the. cylinder 5 and other contained mechanism hereinafterdescribed constitutes an air chamber which forms a cooling jacket aboutthe cylinder 5. In the cylinder 5 reciprocates up and down a striking orpercussion piston 6 consisting of two cylindrical portions connectedtogether and having different diameters. The piston is ung downwards tohammer the strike pin or anvil 10, when the explosive charge in theworking cmpartment 1. of the motor is ignited in a manner sinilar tothat disclosed in the above identified Patent No. 1,920,- 765.Simultaneously the motor piston 8 is pressed upwards and drives theshafty Il by means of the pitman rod 9 and the crank I0. A combined flyand fan wheel i2 is keyed to the shaft and carries a bevel wheel i3meshing with another wheel i4 keyed tov a vertical shaft l5 whichextends downwards and is journalled in a sleeve i6 and provided at itslower end with an eccentric pivot It serving to rotatethe carryingsleeve i.

According to the invention the piston 8 is connected by a rod i8 withthe movable piston I9 in the compressor 2li which in t` e shown exampleis single-acting, and provided at its lower part with an inlet valve 2land an outlet valve 22. The air which by the fany l2 is drawn in throughthe fan opening 23, will pass between the fan andk stationary wall 24 onthe casing. In the space between fan I2 and wall 24 radial or otherwiseshaped blades 25 .are arranged which will exert a centrifugating actionupon the incoming air, so as to remove dust therefrom. In this state theair enters a,y main chamber 26 through an air inlet 1| in the wall 24and which chamber 26 is in open communication with a small chamber 21,from which air is drawn past the valve 2| during the upward stroke ofthe piston I9. When the piston I9 moves downwards, this air is forcedthrough the valve 22 out into a high pressure chamber 28 and thenthrough conduits 29, 30, 3| and port 32 (Figs. 1 and 2) into theinterior of the carrying sleeve of the drill 2, in order to be passed inusual manner through the usual central bore of the drill and reach downinto the borehole to remove dust therein by its blasting action.

Instead of making the air pump separate from the motorcylinder as shownin Fig. 1, this pump may be made in direct connection with the motor asshown in Fig, 2. In this case the motor piston 8 is extended in thedirection towards the crank and provided with a portion 52 of a largerdiameter. This piston portion works in an extension 53 of the motorcylinder 5, the extension 53 having a diameter corresponding to that ofthe piston portion 52, so that there is an annular working space 54 forthe compressor piston 52. This working space is provided at the bottomlaterally with an inlet valve 55 which receives a supply of air from thechamber 26. About at an angular distance of 90 from the inlet valve 55the annular cylinder has an outlet valve 56 as shown in Fig. 2. Fromthis valve a pipe conduit 51 passes through a three-way valve 58 and achannel 59 down to a pressure storage compartment 5| as shown in Figs. 1and 2. The compartment at a certain adjustment of the valve 58 is incommunication with the space or percussion chamber 60 between thestriking piston 6 and the adjacent end of the cylinder 5. Thecompartment 5| for air under pressure operates in a manner formerlyknown, and a definite minimal pressure is maintained therein to act onthe piston 6 to cushion it as it approaches the end of its workingstroke and to return it towards its initial position shown in Fig. 1. Inthe example shown the compressor is now, according to this invention,utilized to supply air und-r pressure to the compartment 5|. Someproportion of the compressed air from chamber 21 in Figure 1 ispassedthrough a valve 41 indicated in Figure 1 as being outside thecasing and a pipe 29 to the compartment. 5|.y The latter is not indirect connection of the carrying sleeve, the connection beingestablished by means of an automatic valve 6| shown in Fig. 3.

This valve controls a port 32' passing into the carrying sleeve andseparated from the compartment 5|, as long as the pressure in thiscompartment is under a certain limit which is determined by a spring 62acting upon the valve sleeve. As soon as the pressure is surpassed, thevalve sleeve 6| will be pressed outwards in Fig. 3, so that thecompartment obtains communication with the port 324 andthe air underpressure is thereby passed to thebore. 'I'he valve 6| operates simulthepressure in the compartment 5| increases so much that the valve 6| inmoving outwards makes pressor is still open. This position of the valve58 is used at the starting of the hammer, in order to have built, up thepressure in the compartment- 5|, before the striking piston is started.

'Ihe compressor may also, as indicated in Fig. 4, be provided with twooutlet valves 22 and 22', the inlet valve being arranged similar to 2|in Figure 1. The valve 22' is located somewhat above the bottom of thecompressor 20 and is by the pipes 29, 30, 3|, 32 in free communicationwith the carrying sleeve of the bit in similar manner as is the conduit29 in Fig. 1. However, the valve 22 is through a pipe 29 incommunication with the pressure compartment 5| in similar manner as thepipe 29 in Figure l. The piston i9 will therefore control thecommunica.- tion between the compressor and the carrying sleeve. Duringthe downward stroke of the piston |9 the substantial part of the airwill be pressed out through the valve 22 and pass to the bore. But assoon as the piston 9 has passed down beyond the valve 22 the air duringthe last part of the working stroke of the piston I9 is pressed throughthe valve 22, the pipe 29 into the pressure compartment 5|. Of course,in this case the pipe 51 is dispensed with. As will be seen, thearrangement of two out-let valves 22 and 22 in Figure 4 is made in asimilar manner and with the same operation as regards the outlet valves56 and 46 respectively in Figure 2.

1. In a device of the class described, the combination of an internalcombustion engine including an engine cylinder, a motor piston operatingtherein, a. freely movable percussion piston having one end mounted inthe cylinder, the compartment formed between the motor piston and thepercussion piston forming a percussion chamber, a drill holder adaptedto receive a drill disposed to be actuated by the percussion piston, anair compressor, a conduit leading therefrom to the drill holder forsupplying air to the drill, said compressor including an air compressingpiston mounted for reciprocatory movement and connected to the motorpiston, said motor piston and percussion piston acting simultaneously onthe firing stroke of the engine to actuate the air compressing piston onits air-intake stroke as the percussion piston moves on its workingstroke, and y--wheel means operatively connected to the motor piston formoving the compressor piston on its air compressing stroke by virtue ofthe inertia of the fiy-Wheel means and thus causing the compressor tosupply air to the drill in said holder following the actuation oftheactuation of the percussion piston thereon at the firing stroke of theengine.

2. In a percussion tool, the combination of a cylinder having a strikingpin mounted at one end and having an air passage for leading air to atool struck by said pin, a floating percussion piston slidably mountedin the cylinder for striking said pin, a power piston reciprocable inthe cylinder, means for actuating said percussion and power pistons, anair compressor opera.- tively connected to said power piston to compressair in relatively large volume, an air conduit leading from thecompressor to said passage in the striking pin, a three-way valve insaid lconduit, another passageway leading from the coduit to the spacebetween the percussion piston and the end of the cylinder containing thestrike pin, said valve disposed in one position to open the conduit tothe space in the cylinder between the percussion piston and the end'ofthe cylinder containing the striking pin and thus disposed to supplycompressed air to cushion the movement of the percussion piston and alsodisposed to open the conduit to supply compressed air to the air passagein the striking pin and said valve in another position closingcommunication between the compressor and said cushioning space in thecylinder while maintaining communication between the compressor and thestriking pin air passage.

3. In a percussion tool, the combination of a cylinder having a strikingpin mounted at one end and having an air passage for leading air to atool actuated by the striking pin, means including said cylinder formingan internal combustion engine and also including a percussion pistonslidably mounted in the cylinder for striking said pin, and a powerpiston reciprocable in the cylinder, an air compressor operativelyconnected to said power piston to compress air, an air conduit leadingfrom the compressor and having capacity to constitute a storagecompartment for compressed air, a three-way valve in said conduit andpassageways leading therefrom, said valve disposed in one position toopen the conduit through one of said passageways to the space in thecylinder between the percussion piston and the end of the cylindercontaining the striking pin and thus supply compressed air to cushionthe movement of the percussion piston and opening the conduit throughanother of said passageways to supply compressed air to the air passagein the striking pin and said valve in another position, closingcommunication between the compressor and said cushioning space whilemaintaining communication between the compressor and the striking pinair passage and valve controlled means for releasing abnormally highpressures in said conduit.

4. In a percussion tool, the combination of means forming an internalcombustion engine including a cylinder, a motor piston reciprocabletherein, a compressor having its piston connected to the motor piston tobe actuated thereby, a percussion piston slidably mounted in saidcylinder, a striking pin slidably mounted to receive the impact or saidpercussion piston at the end of the working strolre thereof and having aconduit therein, a valve controlled conduit leading from the compressorto the conduit in the striking pin, said motor piston acting on thecompressor pieton to draw air into the compressor on the forward orworking stroke ci the motor piston and a flywheel operatively connectedto the compressor piston tok compress the air in the compressor on thenon-working stroke of the motor piston.

5. in a percussion tool, a casing provided at one end with a sleeve forsupporting a drill, said casing containing a cylinder, a motor pistonmounted at one end of the cylinder, a striking piston mounted in thecylinder between the motor piston and the drill supporting sleeve anddisposed to actuate the drill, the .space between the pistons forming acombustion space, an air compressor at the motor end of the cylinderprovided with a compressor piston and operatively connected to the motorpiston to be actuated thereby, and an air conduit leading from thecompressor pastthe motor and striking pistons to the supporting sleeveto supply air to the drill when positioned in the sleeve.

6. In a percussion tool, the combination of a sleeve-like means forcarrying a drill, means for actuating the drill and for supplying airunder compression to the drill, said means including an internalcombustion engine and an air compressor operatively connected lto andactuated thereby with the engine located between the compressor anddrill, and an air conduit for conducting air past the engine andconnecting the compressor with the sleeve-like drill carrying means.

7. A drilling tool of the percussion type, an internal combustion engineincluding a cylinder having a freely floating percussion piston slidablymounted therein, air cushioning means for cushioning the piston at theend of its actuating stroke and for moving it in the opposite directionon its return stroke, means for supplying air to blow debris from thehole formed by the tool, said means including an air compressor providedwith a compressor piston actuated by the engine and said compressoroperatively connected to supply air under compression to said twolast-named means.

8. A drilling tool of the percussion type, an internal combustion engineincluding a cylinder having a freely iloating percussion piston slidablymounted therein, a hole forming tool hammered by paid piston, aircushioning means .for cushioning the piston on its actuating stroke andmeans for supplying air to blow debris from the hole formed by the tool,an air compressor actuated by the engine and operatively connected tosupply airA under compression to said two lastnamed means, and means forautomatically releasing the pressure on the air from the compressorwhenever the pressure exceeds a preset pressure.

9. In a device of the class described'y the cornbination of an internalcombustion chamber including a cylinder, a tool carrier at one end ofthe cylinder, a percussion piston in said cylinder, an air pressurestorage chamber, an air compressor actuated by the engine for supplyingair to said chamber, a conduit leading from said chamber to one end ofsaid cylinder to supply a cushioning medium for the piston as itapproaches one end of its stroke, a conduit leading from said cham.- berto the tool carrier, a release port opening into the atmosphere fromsaid chamber, and a spring pressed relief valve normally closing saidrelease port and opening the same automatically when the pressure insaid chamber exceeds a preset pressure controlled by the tension on thevalve spring.

l0. A percussion tool provided with a casing, an'internal combustionengine including a cylinder contained in the casing and coactingtherewith to provide a cooling space between the cylinder and casing, astriking piston mounted in the cylinder, an air compressor for supplyingcompressed air to the Working side of the percussion piston and providedwith valve controlled inlet and outlet ports, means for supplying air tothe inlet port of the compressor and to said cooling space, said meansincluding a fan actuated by said engine and provided with means forremoving' foreign matter from the air before it is discharged into thecompressor and cooling space,

and a conduit connecting the outlet port of the compressor with theportion of the cylinder between the striking piston and the adjacent endof the cylinder.

11. In a percussion tool, the combination of a drill, mechanism foractuating the drill comprising an internal combustion engine including amotor piston, a compressor connected to the motor piston for supplyingair to the drill, a fan for supplying air to the compressor, meansconnecting the fan and motor piston for causing the piston to rotate thefan and for causing the fan in turn to exert a flywheel 4effect on themotor piston and therethrough on the compressor to move the compressorpiston on its compression stroke by virtue of the inertia of the ywheeland connected parts.

12. In a percussion tool, the combination of a drill, an air compressorfor supplying air under pressure to said drill, power means foractuating both the drill and the air compressor, means forming an airconduit for supplying atmospheric air tothe compressor, means in saidconduit, actuated by said power means for exerting a centrifugatingaction on the air as it is passed to the compressor and thus acting toremove solid matter from the incoming air before it is supplied to thecompressor.

13. In a percussion tool, the combination of a casing provided with astationary wall having an air inlet, mechanism within the casing foractuating a drill, means for supplying air under compression to parts ofsaid mechanism, said means including an air compressor in the casing,means for supplying air to the compressor, said means including a. fanmounted exteriorly of the casing at said inlet, said fan provided in thespace between itself and said wall with blades exerting a centrifugatingaction on the air passing into the air inlet to remove dust therefrombefore it is fed to the compressor.

14. In a percussion tool, the combination of a casing provided with anair inlet, a cylinder in the casing having a lhollow strike pin at oneend, an air compressor at the other end, means for conducting air undercompression from the compressor to the strike pin, a motor piston in thecylinder at the compressor end, a percussion piston in the cylinderbetween the motor piston and the strikepin for hammering the strike pin,a shaft journalled in the casing and driven from the motor piston, adriving connection between the motor piston and the compressor, andmeans for supplying air to the casing interior and to the compressor,said means including a fan at the air inlet driven from said shaft.

15. In a percussion tool, a drill, means for supplying air to the drillincluding a compressor, an internal combustion engine for actuating thedrill and compressor, and means for supplying air to the compressor,said air-supplying means including an air conduit, and a fan thereinactuated by the engine, and said fan provided with means acting on theair as it passes through the conduit for discharging dust from the airas it passes to the compressor.

reclprocatory movement, means connecting the two pistons to cause themto reciprocate in unison, a ywheel and a driving connection between theengine piston and iiywheel.

17. In a percussion tool, the combination of a drill, mechanism foractuating the drill comprising an internal combustion engine including amotor piston, a iiywheel driven from the motor piston and a compressorin fluid communication with the drill for supplying air thereto andincluding a compressor piston coupled to the motor piston to operatetherewith and acting to supply air to the drill, and said compressoractuated through the motor piston by the momentum of the flywheel.

18. In a percussion tool, the combination of a striking piston, and anair compressor operatively connected for supplying compressed air to oneside of the striking piston, an internal combustion engine for operatinglthe piston and compressor, and means for supplying air to thecompressor, said means including a conduit and a fan in said conduit forforcing the air along the conduit to the compressor.

19.'A percussion tool including an air compressor, a drill suppliedwithair from the compressor, an internal combustion engine for actuating thedrill and compressor, and means for supplying air to the compressor,said means including an air conduit, and a fan therein actuated by theengine for forcing the air along said conduit to the compressor.

20. In a percussion tool provided with a mountlng' for a drill and anengine for actuating the drill, means for supplying air under pressureto said mounting, said means including an air compressor of thereciprocating piston type actuated by the engine, said compressorprovided with a valve controlled outlet in spaced relation to thepressure end of the compressor cylinder, and a conduit leading from saidoutlet to said drill mounting.

21. In a percussion tool provided with a mounting for a drill, an enginefor actuating the drill and a pressure storing compartment, means forsupplying air to said mounting and to said compartment, said meansincluding a single acting compressor including a cylinder having apiston reciprocating therein and driven by the engine, said cylinderprovided with two axially spaced apart valve controlled outlets, aconduit leading from one outlet to the drill mounting and an# otherconduit leading'from the other outlet to said compartment.

22. A percussion tool provided with a casing, a cylinder contained inthe casing and co'acting therewith to provide a cooling space betweenthe. cylinder and casing, ,a striking piston mounted in the cylinder, aninternal combustion engine contained in the cylinder and exposed to saidcooling space and operatively connected to the striking' piston toactuate the same, an. air compressor for supplying compressed air to theworking side of the percussion piston and provided with valve controlledinlet and outlet ports, means for supplying air to the inlet port of thecompressor and to said cooling space, said means including a fanactuated by said engine, and a conduit connecting the outlet port of thecompressor with the portion of the cylinder between the striking pistony and the adjacent end of the cylinder.

23. A percussion tool including a casing having an' air inlet, a toolmounted at one end of the casing, mechanism within the 'casing foractuating the tool, means within the tool for supplying a source ofcompressed lair for the tool, a prime mover for actuating said mechanismand means actuated by the prime mover for Aclarifying the air before itis admitted to the casing through said inlet.

24. A percussion tool including a casing having an air inlet, means atone end of the casing for mounting a tool, said means provided with anair passage for supplying air to the tool mounted therein, mechanismincluding an engine within the casing for actuating said tool, meansactuated by the engine for supplying Iair at relatively low pressure tothe casing to cool the cylinder therein and for supplying air atrelatively higher pressure to the air passage in the tool mounting.

25. A pneumatic tool including a casing having an air inlet, and havinga tool mounting a cylinder within the casing having a striking pin atone end for actuating the tool in said mounting, and said cylinderspaced from the casing to form an air-cooling jacket for the cylinder, apercussion piston slidably mounted in the cylinder for striking the pin,means for actuating the percussion piston, mechanism actuated by saidmeans for creating and passing air at a relatively low pressure throughthe air cooling jacket and for introducing air at relatively highpressure into the space between the percussion piston and the adjacentend of the cylinder.

26. A pneumatic tool including a casing having an air inlet and having atool mounting, a cylinder within the casing having a striking pin at oneend for actuating the tool in said mounting, and said cylinder spacedfrom the casing to form an air coo-ling jacket for the cylinder, apercussion piston slidably mounted in the cylinder for striking the pin,means for actuating the percussion piston, mechanism actuated by saidmeans for creating and passing air at ,a relatively low` pressurethrough the air cooling jacket and for introducing air at relativelyhigh pressure into the space between the percussion piston and theadjacent end of the cylinder, and for maintaining a supply of air at thehigh pressure through the tool mounting and in volume ysuflicient toform blasting air for blowing out dirt from the bore being drilled bythe tool.

27; In a percussion tool, the combination of a casing provided at oneend with a cap, a drill mounting sleeve rotatably mounted in the cap, acylinder mounted in the casing spaced therefrom and provided at the endadjacent the mounting with a striking pin having an air passagetherethrough, means including a motor piston slidable in the oppositeend of the cylinder, the part vof the casing beyond the piston end ofthe cylinder forming a mechanism containing an air storage space, acompressor of the reciprocatory piston type mounted in said space andprovided with a valve controlled inlet open to receive air from saidspace, a shaft journalled in said space and having one end projectingexteriorally beyond the casing, said casing provided with an air inletabout the shaft, a crank at the inner end of the shaft, a pitmanconnecting the motor piston and crank, a rod connecting the motorpisto-n and compressor piston, a conduit connecting the discharge portof the compressor with the air passage in the striking pin, ,a fansecured to the protruding end of the shaft for forcing air into said airstorage space and into the space between the cylinder and casing, and adriving connection between the portion of the shaft within the casingand the drill mounting sleeve to rotate the same.

28. In a percussion tool, the combination of a casing provided at oneend with means for rotatably mounting a drill, a cylinder mounted in thecasing and provided at the end adjacent the tool with a striking pin forhammering the tool, mechlanisrn including a motor piston mounted forreciprocatory movement in the cylinder for striking the pin, a shaftjournalled in the casing and driven from the motor piston, and a drivingconnection between the shaft and said means for rotating the drillmounting.

29. In a percussion tool, the combination of a casing provided at oneend with means for rotatably mounting a drill, a cylinder mounted in thecasing and provided at the end adjacent the tool with a striking -pinfor hammering the tool, mechanism including an internal combustionengine with a motor piston mounted for reciprocatory movement in thecylinder for striking the pin, a shaft journalled in the casing anddriven from the motor piston, a driving connection between the shaft andsaid means for rotating the drill mounting, and said driving connectionincluding a shaft mounted in the space between the cylinder and thecasing, extending lengthwise of the tool and having one end geared tothe shaft Iand mounted adjacent its other end in a journalling sleeveand provided at this other end with means for rotating the drillmounting.

LUDVIK RASCH.

